This was decades before my birth, but when I was in junior high or before graduating, I read a book about this tragedy and trial. The title was, I think, Scapegoat, and the author: Anthony Scaduto.
It was a book with enough context and detail to persuade me: the man convicted and executed for these crimes was not guilty. He was poorly represented, and still offered deals to name accomplices.
Richard Hauptmann was an immigrant and from a working class.
Now I may have more sympathy (sometimes) for baby Charles' parents than I once did, and no baby deserves to be kidnapped, etc, but this book turned me to the belief that capital punishment is unacceptable.
And in 2022, the US continues to execute people.